Obesity is a term used to describe body weight that is much greater than what is considered healthy. If you are obese, you have a much higher amount of body fat than lean muscle mass.

Adults with a body mass index (BMI) greater than 25 but less than 30 are considered overweight.

Adults with a BMI greater than 30 are considered obese.

Anyone more than 100 pounds overweight or with a BMI greater than 40 is considered morbidly obese.

Alternative Names:

Morbid obesity; Fat - obese

Causes, incidence, and risk factors:

Rates of obesity are climbing. The percentage of children who are overweight has doubled in the last 20 years. The percentage of adolescents who are obese has tripled in the last 20 years.

Consuming more calories than you burn leads to being overweight and, eventually, obesity. The body stores unused calories as fat. Obesity can be the result of:

Eating more food than the body can use

Drinking too much alcohol

Not getting enough exercise

Certain thyroid problems may also lead to signficant weight gain. Genetic factors play some part in the development of obesity -- children of obese parents are 10 times more likely to be obese than children with parents of normal weight.

Obesity is a significant health threat. The extra weight puts unusual stress on all parts of the body. It raises your risk of diabetes , stroke , heart disease, kidney disease, and gallbladder disease. Conditions such as high blood pressure and high cholesterol, which were once thought to mainly affect adults, are often seen in children who are obese. Obesity may also increase the risk for some types of cancer . Persons who are obese are more likely to develop osteoarthritis and sleep apnea.

Blood tests may be done to look for thyroid or endocrine problems, which could lead to weight gain.

Treatment:

DIET AND EXERCISE

A combination of dieting and exercise (when you stick to it) appears to work better than either one alone. Sticking to a weight reduction program is difficult and requires a lot of support from family and friends.

When dieting, your main goal should be to learn new, healthy ways of eating and make them a part of your everyday routine. Work with your doctor and nutritionist to set realistic, safe daily calorie counts that assure both weight loss and good nutrition. Remember that if you drop pounds slowly and steadily, you are more likely to keep them off. Your nutritionist can teach you about healthy food choices, appropriate portion sizes, and new ways to prepare food.

Even modest weight loss can improve your health. For most people, weight can be lost by eating a healthier diet, exercising more, and adopting new behaviors such as keeping a food diary, avoiding food triggers, and thinking positively.

The decision to keep fit requires a lifelong commitment of time and effort. Patience is essential. You should always check with your health care provider before you begin any new form of exercise.

Several simple behavioral changes can have an impact on your weight loss success:

Eat only at the table. No snacking in front of the TV, in bed, while driving, or while standing in front of the open refrigerator.

Learn about appropriate portion sizes.

Consider learning meditation or yoga as a way of managing stress, rather snacking.

Find ways to socialize and enjoy your friends and family that don't involve a meal or dessert.

Consider keeping a diet and exercise journal. This may help you identify overeating triggers in your life.

Find a support group or consider psychotherapy to help support you in the difficult but worthy goal of weight loss.

Exercise can also help control some of the diseases associated with obesity, including high blood pressure, heart disease, diabetes, osteoporosis, and certain cancers. Exercise is also a major mood lifter, a great way to increase energy, and will help strengthen your bones.

MEDICATIONS AND HERBAL REMEDIES

There are many over-the-counter diet products. Most do not work and some can be dangerous. Before using one, talk to your health care provider.

Several prescription weight loss drugs are available. Such medicines include subutramine (Meridia) and orlistat (Xenical). Ask your health care provider if these are right for you.

While weight loss drugs in general have shown some benefit, the overall weight loss achieved is generally limited. In addition, people will usually regain the weight when they discontinue the medication, unless they have made lasting lifestyle changes.

SURGERY

Surgery may be an option for persons who are morbidly obese and who cannot lose weight using other methods. Weight loss surgery, such as placing adjustable bands around the stomach and gastric bypass surgery , can significantly improve weight and health in the right candidate. Talk to your doctor to learn if this is a good option for you.

Support Groups:

Many people find it easier to follow a diet and exercise program if they join a group of people with similar problems.

Obesity can lead to a gradual decrease in the level of oxygen in your blood, a condition called hypoxemia. Persons who are obese may temporarily stop breathing while asleep (sleep apnea ). Decreased blood oxygen levels and sleep apnea may cause a person to feel sleepy during the day. The conditions may also lead to high blood pressure and pulmonary hypertension . In extreme cases, especially when left untreated, this can lead to right-sided heart failure and ultimately death.

Calling your health care provider:

Schedule an appointment with your health care provider if you or your child are obese or gaining weight at an extremely rapid rate. Remember that catching the problem early is much simpler than trying to fix it after the person has gained an excessive amount of weight.

Prevention:

A healthy diet and regular exercise can help prevent weight gain. Increase your daily activity. Take the stairs rather than the elevator, or walk instead of driving (when possible).

Review Date: 9/7/2008Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.